Here's an update of environmental watering activities for the Loddon Murray wetlands compiled by the North Central Catchment Management Authority.
Environmental watering – autumn 2017 summary
As you are aware, the North Central CMA delivered environmental water to Lake Cullen in spring 2016 and autumn 2017. It has been consistently supporting a high abundance and diversity of wetland birds. Thousands of waterbirds were observed in our recent monitoring including ducks, cormorants, darters, egrets, herons, pelicans and black swans.
Autumn watering at Hird Swamp had demonstrated promising results, most notably at Hird Swamp east, which was watered for the first time in autumn 2017 since the 2011 floods. In our recent monitoring, approximately 400-500 ducks (mainly grey teal) were observed hanging around at Hird Swamp east.
Despite delays due to regulator leakage, autumn watering at Richardson’s Lagoon was successful. A high diversity of waterbirds was consistently observed at Richardson’s Lagoon throughout late autumn and early winter. We have observed that the damaged regulator (eastern end of the link channel) is still leaking despite numerous attempts (applying sandbags and ash) to seal it. The closed regulator acts as a barrier to a pond of nutrient rich water, which is part of the agriculture drainage system. This issue has been flagged with the Victorian Environmental Water Holder (VEWH) and a long term solution will be developed. At this stage, more ash will applied to minimise the leakage prior to our upcoming spring watering in mid-September 2017.
Wirra-Lo Wetland Complex
The North Central CMA delivered environmental water to Duck Creek South and Brolga Swamp at the Wirra-Lo Wetland Complex in autumn 2017. Brolga Swamp is situated on the floodplain of Duck Creek South. Threatened species such as freckled duck and other waterbird species such as black swans, pelicans were observed in the open water environment at Brolga Swamp. Dotterels and lapwings were observed foraging at the edges of the water. Various stiff ground aquatic plants have had positive response to watering.
Upcoming environmental watering events – spring 2017
Environmental water is anticipated to be delivered to Hird Swamp, Richardson’s Lagoon and Wirra-Lo Wetland Complex in September 2017.
It is anticipated that we will deliver environmental water to Hird Swamp in mid-September 2017 at 40 ML/day (approximately 1300 ML required). The watering objective is to fill both Hird Swamp east and west to support waterbird breeding, and provide important waterbird habitat. Under the Native Fish Recovery Plan, the CMA has reinstated around 30 complexes of instream woody habitat (snags) in the creek, and has delivered a number of environmental watering events to encourage fish movement through the creek. A series of top ups will be delivered to Hird Swamp as required. During one of these events, water will be delivered through Hird Swamp into Pyramid Creek as a through flow to provide a source of carbon and nutrients as the inputs to the food web (e.g. biofilms on the snags and waterbugs) which in turn provide food for native fish. Fish ecologists from the Arthur Rylah Institute have advised juvenile golden and silver perch will be expected to move actively in summer and may possibly use the creek. Monitoring has shown that some large Murray cods have moved in and are using the newly reinstated snags as their habitat. It is important to note that this through flow will not affect the water levels at Hird Swamp.
Environmental water is anticipated to be delivered to Richardson’s Lagoon in early September 2017 at 30 ML/day (approximately 500 ML required) pumping from the Murray River into the wetland via a link channel. The watering objective is to fill Richardson’s Lagoon and achieve floodplain inundation to support a range of flora and fauna species, and habitat functions including waterbird resting, nesting and feeding.
Wirra-Lo Wetland Complex
Environmental water is anticipated to be delivered to Wirra-Lo Wetland Complex in mid/late September 2017 at 10 ML/day (approximately 100 ML required). The watering objective is to top up Duck Creek South and Brolga Swamp, and fill Duck Creek North to provide refuge habitat and suitable breeding conditions for growling grass frog as well as creating high quality feeding and breeding habitat for waterbirds.
Ecologists from the Arthur Rylah Institute are monitoring the above wetlands to determine the vegetation, waterbird and frog responses to environmental watering under the state Wetland Monitoring and Assessment Program (WetMAP). We will keep you up to date on their findings.